HVAC RTU weight R22 vs R410a 1

[efsinc]

Hello,
I'm visiting as a structural engineer looking for some guidance. I've been told that R410a HVAC RTU equipment will weigh more than R22 HVAC RTU equipment of the same capacity. This is important as I advise my client of structural engineering issues for his retail buildings as he replaces older equipment. Can you please advise me on this? Is it true? Why is it true? Where might I obtain some technical literature on this?

Thank you for helping out this structural engineer here.

 

[MintJulep]

The answer is "it depends".

R410a is not quite as good a refrigerant as R22, so the heat exchanges need to be a bit bigger for the same capacity.

R410a operates at higher pressure that R22, so some components might need to be stronger (and thus heavier).

But

If you are replacing old R22 equipment of any size the chances are that it had a cast iron body semi-hermetic compressor.

The new R410a equipment will probably have scroll compressors. They are lighter for the same capacity.

Except that

The new equipment might have two or three or four scroll compressors in place of one or two cast iron compressors to allow for modulation and unloading. That sort of negates the lighterness of the scroll compressor design.

And those extra compressors come with extra piping, valves and wiring.

Of course

Where the old equipment might have had copper condenser tubes and copper fins then new might (or might not) have aluminum tubes and fins, or copper tubes and aluminum fins, or aluminum micro-channel heat exchangers even.

So basically, you need to ask the HVAC engineer what he wants to use, or give him a maximum weight.

 

[KiwiMace]

Also, the mandatory minimum efficiency (SEER) ratings have gone up over the last few years which has likewise increased the size of the unit heat exchangers.

I'd conservatively guess that the weights have gone up a bit, certainly the physical size has. Send the equipment numbers to the local vendor and ask them what the old weights were, the recommended replacements and new weights.

Remember to include the curb weights, which are by a different vendor.

 

[efsinc]

Thank you both! This is most informative. Best regards.